The present invention relates to scroll compressors. More specifically, the present invention relates to the controlled flow of lubricant and gas in and through a low-side scroll refrigerant compressor.
Low-side compressors are compressors in which the motor by which the compression mechanism is driven is disposed in the low or suction pressure portion of the compressor shell. In the case of a scroll compressor, the motor drives one of two scroll members which are constrained, by the use of a device such as an Oldham coupling, to movement such that one scroll member orbits with respect to the other.
Such orbital motion, in the proper direction, causes the cyclical creation of pockets at the radially outward ends of the interleaved involute wraps of the scroll members. Such pockets fill with suction gas, close and are displaced radially inward, compressing the gas trapped therein in the process. The compression pockets are displaced into communication with a discharge port at the center of the scroll set and the compressed gas is expelled therethrough.
In low-side scroll compressors used in refrigeration applications, refrigerant gas at suction pressure must be delivered to the vicinity of the suction pockets cyclically defined by the radially outward ends of the wraps of the scroll members. Unless a suction tube of some sort is used, a portion of the compressor shell and/or a frame in the shell of the compressor will most typically define at least a portion of the flow path by which such suction gas is delivered from exterior of the compressor shell to the suction pockets.
As is typical in most compressors, the motors by which scroll compressors are driven must be proactively cooled in order to prevent their overheating during operation. Further, provision must be made for the lubrication of the bearings in which the drive shaft and driven scroll member rotates as well as for the lubrication of other surfaces in the compressor, including thrust surfaces and the surfaces of compressor components, such as the Oldham coupling.
The flow and delivery of lubricant to surfaces requiring lubrication through the low-side of the shell of a scroll compressor, its interaction with the suction gas flowing therethrough to the compression mechanism and the need to cool the motor by which the drive scroll member is driven all create the need to carefully manage and control the flow, use, interaction and separation of lubricant and gas in a low-side scroll compressor to maximize compressor efficiency and to ensure that sufficient lubricant remains in the shell and is not carried thereoutof in the gas which undergoes compression.